Comprehensive blueprint of Salmonella genomic plasticity identifies hotspots for pathogenicity genes.

Understanding the dynamic evolution of Salmonella is vital for effective bacterial infection management. This study explores the role of the flexible genome, organised in regions of genomic plasticity (RGP), in shaping the pathogenicity of Salmonella lineages. Through comprehensive genomic analysis of 12,244 Salmonella spp. genomes covering 2 species, 6 subspecies, and 46 serovars, we uncover distinct integration patterns of pathogenicity-related gene clusters into RGP, challenging traditional views of gene distribution. These RGP exhibit distinct preferences for specific genomic spots, and the presence or absence of such spots across Salmonella lineages profoundly shapes strain pathogenicity. RGP preferences are guided by conserved flanking genes surrounding integration spots, implicating their involvement in regulatory networks and functional synergies with integrated gene clusters. Additionally, we emphasise the multifaceted contributions of plasmids and prophages to the pathogenicity of diverse Salmonella lineages. Overall, this study provides a comprehensive blueprint of the pathogenicity potential of Salmonella. This unique insight identifies genomic spots in nonpathogenic lineages that hold the potential for harbouring pathogenicity genes, providing a foundation for predicting future adaptations and developing targeted strategies against emerging human pathogenic strains.

A Newly Incompatibility F Replicon Allele (FIB81) in Extensively Drug-Resistant Escherichia coli Isolated from Diseased Broilers.

Multiple drug resistance (MDR) has gained pronounced attention among Enterobacterales. The transfer of multiple antimicrobial resistance genes, frequently carried on conjugative incompatibility F (IncF) plasmids and facilitating interspecies resistance transmission, has been linked to Salmonella spp. and E. coli in broilers. In Egypt, the growing resistance is exacerbated by the limited clinical efficacy of many antimicrobials. In this study, IncF groups were screened and characterized in drug-resistant Salmonella spp. and E. coli isolated from broilers. The antimicrobial resistance profile, PCR-based replicon typing of bacterial isolates pre- and post-plasmid curing, and IncF replicon allele sequence typing were investigated. Five isolates of E. coli (5/31; 16.13%) and Salmonella spp. (5/36; 13.89%) were pan-susceptible to the examined antimicrobial agents, and 85.07% of tested isolates were MDR and extensively drug-resistant (XDR). Twelve MDR and XDR E. coli and Salmonella spp. isolates were examined for the existence of IncF replicons (FII, FIA, and FIB). They shared resistance to ampicillin, ampicillin/sulbactam, amoxicillin/clavulanate, doxycycline, cefotaxime, and colistin. All isolates carried from one to two IncF replicons. The FII-FIA-FIB+ and FII-FIA+FIB- were the predominant replicon patterns. FIB was the most frequently detected replicon after plasmid curing. Three XDR E. coli isolates that were resistant to 12-14 antimicrobials carried a newly FIB replicon allele with four nucleotide substitutions: C99→A, G112→T, C113→T, and G114→A. These findings suggest that broilers are a significant reservoir of IncF replicons with highly divergent IncF-FIB plasmid incompatibility groups circulating among XDR Enterobacterales. Supporting these data with additional comprehensive epidemiological studies involving replicons other than the IncF can provide insights for implementing efficient policies to prevent the spreading of new replicons to humans.

An all-in-one microfluidic SlipChip for power-free and rapid biosensing of pathogenic bacteria.

Point-of-care testing of pathogens is becoming more and more important for the prevention and control of food poisoning. Herein, a power-free colorimetric biosensor was presented for rapid detection of Salmonella using a microfluidic SlipChip for fluidic control and Au@PtPd nanocatalysts for signal amplification. All the procedures, including solution mixing, immune reaction, magnetic separation, residual washing, mimicking catalysis and colorimetric detection, were integrated on this SlipChip. First, the mixture of the bacterial sample, immune magnetic nanobeads (IMBs) and immune Au@PtPd nanocatalysts (INCs), washing buffer and H2O2-TMB chromogenic substrate were preloaded into the sample, washing and catalysis chambers, respectively. After the top layer of this SlipChip was slid to connect the sample chamber with the separation chamber, the mixture was moved back and forth through the asymmetrical split-and-recombine micromixer by using a disposable syringe to form the IMB-Salmonella-INC sandwich conjugates. Then, the conjugates were captured in the separation chamber using a magnetic field, and the top layer was slid to connect the washing chamber with the separation chamber for washing away excessive INCs. Finally, the top layer was slid to connect the catalysis chamber with the separation chamber, and the colorless substrate was catalyzed by the INCs with peroxidase-mimic activity to generate color change, followed by using a smartphone app to collect and analyze the image to determine the bacterial concentration. This all-in-one microfluidic biosensor enabled simple detection of Salmonella as low as 101.2 CFU mL-1 within 30 min and was featured with low cost, straightforward operation, and compact design.

Label-free multi-line immunochromatographic sensor based on TCBPE for broad-spectrum detection Salmonella in food.

BACKGROUND: Salmonella, a foodborne pathogen poses significant threats to food safety and human health. Immunochromatographic (ICTS) sensors have gained popularity in the field of food safety due to their convenience, speed, and cost-effectiveness. However, most existing ICTS sensors rely on antibody sandwich structures which are limited by their dependence on high-quality paired antibodies and restricted sensitivity. For the first time, we combined multi-line ICTS strips with fluorescent bacterial probes to develop a label-free multi-line immunochromatographic sensor capable of detecting broad-spectrum Salmonella. Salmonella was labeled with the aggregation-induced luminescence material TCBPE, resulting in its transformation into a green fluorescent probe. RESULTS: Using this sensor, we successfully detected Salmonella typhimurium within the concentration range of 104-108 CFU/mL with a visual detection limit of 6.0 × 104 CFU/mL. Compared to single-line sensors, our multi-line sensor exhibited significantly improved fluorescence intensity resulting in enhanced detection sensitivity by 50 %. Furthermore, our developed multi-line ICTS sensor demonstrated successful detection of 18 different strains of Salmonella without any cross-reaction observed with 5 common foodborne pathogens tested. The applicability and reliability were validated using milk samples, cabbage juice samples as well and drinking water samples suggesting its potential for rapid and accurate detection of Salmonella in real-world scenarios across both the food industry and clinical settings. SIGNIFICANCE: In this experiment, we developed a TCBPE-based multiline immunochromatographic sensor. Specifically, Salmonella was labeled with the aggregation-induced luminescence material TCBPE, resulting in its transformation into a green fluorescent probe. Through the multi-line analysis system, the detection sensitivity and accuracy of the sensor are improved. In brief, the sensor does not require complex antibody labeling and paired antibodies, and only one antibody is needed to complete the detection process.

Salmonella Prevalence and antibiotic resistance profile in raw poultry meat sold in North Lebanon: Insights from the COVID-19 pandemic and economic crisis.

Salmonella-related foodborne illness is a significant public health concern, with the primary source of human infection being animal-based food products, particularly chicken meat. Lebanon is currently experiencing a dual crisis: the COVID-19 pandemic and an unprecedented economic crisis, which has resulted in substantial challenges to the public health system and food safety. This study aims to assess the prevalence and antibiotic resistance profile of Salmonella in raw poultry meat sold in North Lebanon during this dual crisis. A cross-sectional study was carried out between May 2021 and April 2022 across six different districts in North Lebanon. A total of 288 whole, unprocessed chickens were examined. The isolation and identification of Salmonella isolates were done based on cultural and biochemical properties. All isolates were subjected to antimicrobial susceptibility testing and phenotypic assays for Extended-Spectrum Beta-lactamase (ESBL) detection. The prevalence of Salmonella in raw poultry meat purchased in North Lebanon reached 18.05 % (52/288). The dry season and chilled chicken were significantly associated with an increased risk of Salmonella contamination (P < 0.05). Additionally, 34.61 % of the isolates were potential ESBL producers, and 57.69 % exhibited multidrug resistance (MDR). This study highlights the existence of MDR in chicken meat in North Lebanon, posing a potential health risk if undercooked chicken meat is consumed. This emphasizes the importance of the implementation of preventive strategies and hygienic procedures throughout the food chain to reduce the risk of Salmonella spp. contamination in chicken meats and its potential transmission to humans.

Structure, biosynthesis and regulation of the T1 antigen, a phase-variable surface polysaccharide conserved in many Salmonella serovars.

The bacterial genus Salmonella includes diverse isolates with multiple variations in the structure of the main polysaccharide component (O antigen) of membrane lipopolysaccharides. In addition, some isolates produce a transient (T) antigen, such as the T1 polysaccharide identified in the 1960s in an isolate of Salmonella enterica Paratyphi B. The structure and biosynthesis of the T1 antigen have remained enigmatic. Here, we use biophysical, biochemical and genetic methods to show that the T1 antigen is a complex linear glycan containing tandem homopolymeric domains of galactofuranose and ribofuranose, linked to lipid A-core, like a typical O antigen. T1 is a phase-variable antigen, regulated by recombinational inversion of the promoter upstream of the T1 genetic locus through a mechanism not observed for other bacterial O antigens. The T1 locus is conserved across many Salmonella isolates, but is mutated or absent in most typhoidal serovars and in serovar Enteritidis.

Structure and rational engineering of the PglX methyltransferase and specificity factor for BREX phage defence.

Bacteria have evolved a broad range of systems that provide defence against their viral predators, bacteriophages. Bacteriophage Exclusion (BREX) systems recognise and methylate 6 bp non-palindromic motifs within the host genome, and prevent replication of non-methylated phage DNA that encodes these same motifs. How BREX recognises cognate motifs has not been fully understood. In this study we characterise BREX from pathogenic Salmonella and present X-ray crystallographic structures of the conserved BREX protein, PglX. The PglX N-terminal domain encodes the methyltransferase, whereas the C-terminal domain is for motif recognition. We also present the structure of PglX bound to the phage-derived DNA mimic, Ocr, an inhibitor of BREX activity. Our analyses propose modes for DNA-binding by PglX and indicate that both methyltransferase activity and defence require larger BREX complexes. Through rational engineering of PglX we broaden both the range of phages targeted, and the host motif sequences that are methylated by BREX. Our data demonstrate that PglX is used to recognise specific DNA sequences for BREX activity, contributing to motif recognition for both phage defence and host methylation.

An electrochemical biosensor for sensitive detection of live Salmonella in food via MXene amplified methylene blue signals and electrostatic immobilization of bacteriophages.

A novel bacteriophage-targeted electrochemical biosensor designed for accurate and quantitative detection of live Salmonella in food samples is presented. The biosensor is simply constructed by electrostatic immobilizing bacteriophages on MXene-nanostructured electrodes. MXene, renowned for its high surface area, biocompatibility, and conductivity, serves as an ideal platform for bacteriophage immobilization. This allows for a high-density immobilization of bacteriophage particles, achieving approximately 71 pcs µm-2. Remarkably, the bacteriophages immobilized MXene nanostructured electrodes still maintain their viability and functionality, ensuring their effectiveness in pathogen detection. Therefore, the proposed biosensor exhibited enhanced sensitivity with a low limit of detection (LOD) of 5 CFU mL-1. Notably, the biosensor shows excellent specificity in the presence of other bacteria that commonly contaminate food and can distinguish live Salmonella from a mixed population. Furthermore, it is applicable in detecting live Salmonella in food samples, which highlights its potential in food safety monitoring. This biosensor offers simplicity, convenience, and suitability for resource-limited environments, making it a promising tool for on-site monitoring of foodborne pathogenic bacteria.

Rapid detection of ceftriaxone-resistant Salmonella by matrix-assisted laser desorption-ionization time-of-flight mass spectrometry combined with the ratio of optical density.

BACKGROUND: The increased resistance rate of Salmonella to third-generation cephalosporins represented by ceftriaxone (CRO) may result in the failure of the empirical use of third-generation cephalosporins for the treatment of Salmonella infection in children. The present study was conducted to evaluate a novel method for the rapid detection of CRO-resistant Salmonella (CRS). METHODS: We introduced the concept of the ratio of optical density (ROD) with and without CRO and combined it with matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF MS) to establish a new protocol for the rapid detection of CRS. RESULTS: The optimal incubation time and CRO concentration determined by the model strain test were 2 h and 8 µg/ml, respectively. We then conducted confirmatory tests on 120 clinical strains. According to the receiver operating characteristic curve analysis, the ROD cutoff value for distinguishing CRS and non-CRS strains was 0.818 [area under the curve: 1.000; 95% confidence interval: 0.970-1.000; sensitivity: 100.00%; specificity: 100%; P < 10- 3]. CONCLUSIONS: In conclusion, the protocol for the combined ROD and MALDI-TOF MS represents a rapid, accurate, and economical method for the detection of CRS.

Prevalence and antimicrobial susceptibility profile of Salmonella isolated from vegetable farms fertilized with animal manure in Addis Ababa Ethiopia.

The resistance of foodborne pathogens to antimicrobial agents is a potential danger to human health. Hence, establishing the status of good agricultural practices (GAPs) and the antimicrobial susceptibility of major foodborne pathogens has a significant programmatic implication in planning interventions. The objective of this study was to assess the gap in attaining GAP and estimate the prevalence and antimicrobial susceptibility profile of Salmonella in vegetable farms fertilized with animal manure in Addis Ababa, Ethiopia. A total of 81 vegetable farms from four sub-cities in Addis Ababa were visited, and 1119 samples were collected: soil (n = 271), manure (n = 375), vegetables (n = 398), and dairy cattle feces (n = 75). Additional data were collected using a structured questionnaire. Isolation of Salmonella was done using standard microbiology techniques and antimicrobial susceptibility testing was conducted using disk diffusion assays. Carriage for antimicrobial resistance genes was tested using polymerase chain reaction (PCR). Among the 81 vegetable farms visited, 24.7% used animal manure without any treatment, 27.2% used properly stored animal manure and 80.2% were easily accessible to animals. The prevalence of Salmonella was 2.3% at the sample level, 17.3% at the vegetable farm level, and 2.5% in vegetables. The highest rate of resistance was recorded for streptomycin, 80.7% (21 of 26), followed by kanamycin, 65.4% (17 of 26), and gentamicin, 61.5% (16 of 26). Multidrug resistance was detected in 61.5% of the Salmonella isolates. Vegetable farms have a gap in attaining GAPs, which could contribute to increased contamination and the transfer of antimicrobial resistance to the vegetables. The application of GAPs, including proper preparation of compost and the appropriate use of antimicrobials in veterinary practices, are recommended to reduce the emergence and spread of antimicrobial resistance.

Calidad higiénico-sanitaria y prácticas de manufactura de alimentos en un comedor estudiantil en México / Hygienic ­ sanitary quality and food manufacturing practices in a student cafeteria in Mexico / Qualidade higiênico-sanitária e práticas de fabricação de alimentos em uma refeitório estudantil no México

Introducción: El apego a las normas oficiales sanitarias sirve para prevenir riesgos a la salud humana. Objetivo: Evaluar la calidad higiénico-sanitaria y las buenas prácticas de manufactura de alimentos (BPMA) de un comedor estudiantil en México. Materiales y métodos: Estudio cuasiexperimental y analítico. Durante el año 2020, se realizaron pruebas bacteriológicas a muestras de alimentos, agua, superficies y manos de manipuladores de alimentos, además de también evaluar las BPMA. Conforme a las normas oficiales sanitarias vigentes en México, se recolectaron 57 muestras, se aislaron y se lograron identificar patógenos. Las BPMA se valoraron en 20 manipuladores, antes y después de una intervención educativa de 10 semanas de duración y se utilizó la prueba t con α=0,05. Resultados: Más del 50 % de las muestras resultaron con microorganismos de riesgo para la salud, como Escherichia coli, Staphylococcus aureus, Pseudomonas, Acinetobacter baumanni complex y Coliformes totales. Las evaluaciones, antes y después de la intervención educativa de BPMA, evidenciaron diferencias estadísticamente significativas en el número de aciertos (p≤0,05). Conclusiones: La calidad higiénico-sanitaria del comedor analizado representó riesgo para la salud de los estudiantes, lo cual tuvo relación con la primera evaluación de las BPMA entre los manipuladores, las cuales mejoraron después de la intervención.

Introduction: Adherence to official health standards is essential to prevent human health risks. Objective: To assess the hygienic-sanitary quality and good food manufacturing practices (GMP) in a student cafeteria in Mexico. Materials and methods: Quasi-experimental and analytical study. During 2020, bacteriological tests were carried out on samples taken from food, water, surfaces, and hands of food handlers. In addition, GMP were evaluated. Based on the current Mexican official health regulations, 57 samples were collected to isolate and identify pathogens. GMP were assessed in 20 food handlers before and after a 10-week training intervention and a test was used with α=0.05. Results: More than 50% of samples were found to have microorganisms associated with health risks, including Escherichia coli, Staphylococcus aureus, Pseudomonas, Acinetobacter baumanni complex and total Coliforms. The analyses before and after the GMP training intervention showed statistically significant differences in terms of the presence of these pathogens (p≤0.05). Conclusions: The hygienic-sanitary quality of the analyzed cafeteria turned out to be a risk for the health of students, which was related to the first assessment of GMP in food handlers. Consequently, the results improved after the intervention.

Introdução: A adesão às normas sanitárias oficiais serve para prevenir riscos à saúde humana. Objetivo: Avaliar a qualidade higiênico-sanitária e as boas práticas de fabricação de alimentos (BPMA) de um refeitorio estudantil no México. Materiais e métodos: Estudo quase-experimental e analítico. Durante 2020, foram realizados testes bacteriológicos em amostras de alimentos, água, superfícies e mãos de manipuladores de alimentos, além de avaliação de BPMA. De acordo com as normas sanitárias oficiais em vigor no México, foram coletadas e isoladas 57 amostras e identificados patógenos. Os BPMA foram avaliados em 20 manipuladores, antes e após uma intervenção educativa de 10 semanas e foi utilizado o teste t com α=0,05. Resultados: Verificou-se que mais de 50% das amostras continham microrganismos de risco à saúde, como Escherichia coli, Staphylococcus aureus, Pseudomonas, complexo Acinetobacter baumanni e Coliformes totais. As avaliações, antes e após a intervenção educativa BPMA, apresentaram diferenças estatisticamente significativas no número de acertos (p≤0,05). Conclusões: A qualidade higiênico-sanitária do refeitório analisado representou um risco para a saúde dos alunos, o que esteve relacionado à primeira avaliação do BPMA entre os manipuladores, que melhorou após a intervenção.

Prevalence and antimicrobial resistance of salmonellae isolated from eggs of local chicken in selected towns of Ethiopia.

BACKGROUND: Salmonellosis is one of the most common food-borne diseases in industrialised and developing countries. In recent year, an increase in antimicrobial resistance among different Salmonella serotypes has been observed. OBJECTIVE: A cross-sectional study was conducted to assess the prevalence and antimicrobial susceptibility of Salmonella isolated from local chicken eggs in four selected towns in Ethiopia. METHODS: A total of 115 eggs were examined to detect Salmonella by using standard microbiological methods. The susceptibilities of the isolates to nine antimicrobials were tested by the Kirby-Bauer disk diffusion method. RESULT: The study revealed that of the 115 eggs examined, 22 (19.1%) were positive for Salmonella of which 14 (12.2%) and 8 (7%) of the isolates were from shells and contents, respectively. The occurrence of Salmonella in egg shells and content and between different altitudes did not differ significantly (p > 0.05). Most isolates were resistant to more than three antimicrobials with a high resistance to kanamycin, ampicillin, nalidixic acid, cotrimoxazole, oxytetracycline and chloramphenicol. CONCLUSION: The results indicate the potential importance of local chicken eggs as source of multiple antimicrobial-resistant salmonellae and the need for proper cooking before consumption. Further studies are required to describe the epidemiology of Salmonella in various agroclimatic zones of Ethiopia.

History repeats itself: consumption of a local traditional roast pork meat recipe leads to Salmonella ser. Give cases in Greece.

INTRODUCTION: An outbreak of gastroenteritis due to Salmonella Give, a very rarely identified serotype in human isolates in Greece, occurred in participants of a religious festival in a rural area of southern Greece, in September 2022. The objectives of this study were to describe the outbreak in terms of epidemiology, identify the vehicle of transmission of the foodborne pathogen and recommend prevention measures. METHODS: The outbreak was linked to the consumption of a local traditional recipe of roasted pork meat served by a street food vendor. In 2018, the same food item, served in a restaurant in the same region, was implicated in another S. Give outbreak. RESULTS: Outbreak investigations revealed that outbreak-associated isolates, of food and human origin, belonged to the same S. Give strain. Significant deficiencies regarding food safety practices were identified. CONCLUSION: Technical knowledge about pathogen transmission paths is important in order for both food handlers and consumers to follow hygiene and sanitary measures, mainly in cases of mass gatherings, where large quantities of food are prepared, handled, cooked and served. Efficient official supervision, mainly during summer festivals, is required in order to avoid recurrence of foodborne infections by different combinations of pathogens/food commodities.

Enhancing Nanobody Immunoassays through Ferritin Fusion: Construction of a Salmonella-Specific Fenobody for Improved Avidity and Sensitivity.

Nanobodies (Nbs) serve as powerful tools in immunoassays. However, their small size and monovalent properties pose challenges for practical application. Multimerization emerges as a significant strategy to address these limitations, enhancing the utilization of nanobodies in immunoassays. Herein, we report the construction of a Salmonella-specific fenobody (Fb) through the fusion of a nanobody to ferritin, resulting in a self-assembled 24-valent nanocage-like structure. The fenobody exhibits a 35-fold increase in avidity compared to the conventional nanobody while retaining good thermostability and specificity. Leveraging this advancement, three ELISA modes were designed using Fb as the capture antibody, along with unmodified Nb422 (FbNb-ELISA), biotinylated Nb422 (FbBio-ELISA), and phage-displayed Nb422 (FbP-ELISA) as the detection antibody, respectively. Notably, the FbNb-ELISA demonstrates a detection limit (LOD) of 3.56 × 104 CFU/mL, which is 16-fold lower than that of FbBio-ELISA and similar to FbP-ELISA. Moreover, a fenobody and nanobody sandwich chemiluminescent enzyme immunoassay (FbNb-CLISA) was developed by replacing the TMB chromogenic substrate with luminal, resulting in a 12-fold reduction in the LOD. Overall, the ferritin-displayed technology represents a promising methodology for enhancing the detection performance of nanobody-based sandwich ELISAs, thereby expanding the applicability of Nbs in food detection and other fields requiring multivalent modification.

Phenotypic characterization and genomic analysis of a Salmonella phage L223 for biocontrol of Salmonella spp. in poultry.

The escalating incidence of foodborne salmonellosis poses a significant global threat to food safety and public health. As antibiotic resistance in Salmonella continues to rise, there is growing interest in bacteriophages as potential alternatives. In this study, we isolated, characterized, and evaluated the biocontrol efficacy of lytic phage L223 in chicken meat. Phage L223 demonstrated robust stability across a broad range of temperatures (20-70 °C) and pH levels (2-11) and exhibited a restricted host range targeting Salmonella spp., notably Salmonella Typhimurium and Salmonella Enteritidis. Characterization of L223 revealed a short latent period of 30 min and a substantial burst size of 515 PFU/cell. Genomic analysis classified L223 within the Caudoviricetes class, Guernseyvirinae subfamily and Jerseyvirus genus, with a dsDNA genome size of 44,321 bp and 47.9% GC content, featuring 72 coding sequences devoid of antimicrobial resistance, virulence factors, toxins, and tRNA genes. Application of L223 significantly (p < 0.005) reduced Salmonella Typhimurium ATCC 14,028 counts by 1.24, 2.17, and 1.55 log CFU/piece after 2, 4, and 6 h of incubation, respectively, in experimentally contaminated chicken breast samples. These findings highlight the potential of Salmonella phage L223 as a promising biocontrol agent for mitigating Salmonella contamination in food products, emphasizing its relevance for enhancing food safety protocols.

An integrated comparative genomics, subtractive proteomics and immunoinformatics framework for the rational design of a Pan-Salmonella multi-epitope vaccine.

Salmonella infections pose a significant global public health concern due to the substantial expenses associated with monitoring, preventing, and treating the infection. In this study, we explored the core proteome of Salmonella to design a multi-epitope vaccine through Subtractive Proteomics and immunoinformatics approaches. A total of 2395 core proteins were curated from 30 different isolates of Salmonella (strain NZ CP014051 was taken as reference). Utilizing the subtractive proteomics approach on the Salmonella core proteome, Curlin major subunit A (CsgA) was selected as the vaccine candidate. csgA is a conserved gene that is related to biofilm formation. Immunodominant B and T cell epitopes from CsgA were predicted using numerous immunoinformatics tools. T lymphocyte epitopes had adequate population coverage and their corresponding MHC alleles showed significant binding scores after peptide-protein based molecular docking. Afterward, a multi-epitope vaccine was constructed with peptide linkers and Human Beta Defensin-2 (as an adjuvant). The vaccine could be highly antigenic, non-toxic, non-allergic, and have suitable physicochemical properties. Additionally, Molecular Dynamics Simulation and Immune Simulation demonstrated that the vaccine can bind with Toll Like Receptor 4 and elicit a robust immune response. Using in vitro, in vivo, and clinical trials, our findings could yield a Pan-Salmonella vaccine that might provide protection against various Salmonella species.

Incidence, identification and antibiotic resistance of Salmonella spp. in the well waters of Tadla Plain, Morocco.

Concerns about challenges with water availability in the Tadla Plain region of Morocco have grown as a result of groundwater contamination brought on by human activity, climate change, and insufficient groundwater management. The objective of the study is to measure the number of resistant bacteria in the groundwater of Beni Moussa and Beni Aamir, as well as to evaluate the level of water pollution in this area. 200 samples were therefore gathered from 43 wells over the course of four seasonal campaigns in 2017 and 2018. Additionally, the samples were examined to determine whether Salmonella species were present and if they were resistant to the 16 antibiotics that were tested. Salmonella spp. have been identified in 31 isolated strains in total, accounting for 18.02% of all isolated strains. Data on antibiotic resistance show that 58.1% of Salmonella spp. strains are multidrug-resistant (MDR); 38.7% of Salmonella strains are tolerant to at least six antibiotics, 19.4% to at least nine antibiotics, 9.7% to four to seven antibiotics, 6.5% to at least eleven antibiotics, and the remaining 3.2% to up to twelve antibiotics. A considerable level of resistance to cefepime (61.29%), imipenem (54.84%), ceftazidime (45.16%), ofloxacin (70.97%), and ertapenem (74.19%) was found in the data. Consequently, it is important to monitor and regulate the growth of MDR in order to prevent the groundwater's quality from declining.

A secondary abdominal aorta-duodenal fistula accompanied with acquired Immune Deficiency Syndrome presented with recurrent sepsis: a case report.

BACKGROUND: Abdominal aorta-duodenal fistulas are rare abnormal communications between the abdominal aorta and duodenum. Secondary abdominal aorta-duodenal fistulas often result from endovascular surgery for aneurysms and can present as severe late complications. CASE PRESENTATION: A 50-year-old male patient underwent endovascular reconstruction for an infrarenal abdominal aortic pseudoaneurysm. Prior to the operation, he was diagnosed with Acquired Immune Deficiency Syndrome and Syphilis. Two years later, he was readmitted with lower extremity pain and fever. Blood cultures grew Enterococcus faecium, Salmonella, and Streptococcus anginosus. Sepsis was successfully treated with comprehensive anti-infective therapy. He was readmitted 6 months later, with blood cultures growing Enterococcus faecium and Escherichia coli. Although computed tomography did not show contrast agent leakage, we suspected an abdominal aorta-duodenal fistula. Esophagogastroduodenoscopy confirmed this suspicion. The patient underwent in situ abdominal aortic repair and received long-term antibiotic therapy. He remained symptom-free during a year and a half of follow-up. CONCLUSIONS: This case suggests that recurrent infections with non-typhoidal Salmonella and gut bacteria may be an initial clue to secondary abdominal aorta-duodenal fistula.

Prospective modeling and estimating the epidemiologically informative match rate within large foodborne pathogen genomic databases.

OBJECTIVES: Much has been written about the utility of genomic databases to public health. Within food safety these databases contain data from two types of isolates-those from patients (i.e., clinical) and those from non-clinical sources (e.g., a food manufacturing environment). A genetic match between isolates from these sources represents a signal of interest. We investigate the match rate within three large genomic databases (Listeria monocytogenes, Escherichia coli, and Salmonella) and the smaller Cronobacter database; the databases are part of the Pathogen Detection project at NCBI (National Center for Biotechnology Information). RESULTS: Currently, the match rate of clinical isolates to non-clinical isolates is 33% for L. monocytogenes, 46% for Salmonella, and 7% for E. coli. These match rates are associated with several database features including the diversity of the organism, the database size, and the proportion of non-clinical BioSamples. Modeling match rate via logistic regression showed relatively good performance. Our prediction model illustrates the importance of populating databases with non-clinical isolates to better identify a match for clinical samples. Such information should help public health officials prioritize surveillance strategies and show the critical need to populate fledgling databases (e.g., Cronobacter sakazakii).

Bacteriological quality and physicochemical analysis of the Kalte River at Wolaita Sodo Town, southern Ethiopia.

OBJECTIVE: The current research aimed to investigate the physicochemical and bacteriological quality status of the Kalte River in Wolaita Sodo Town, southern Ethiopia. METHODS: A total of 42 water samples were collected using sterile glass bottles from three different river sites: Damota (upstream), Kera (midstream), and Gututo (downstream). All the water samples were examined for the presence of heterotrophic bacteria, total coliform and fecal coliform using direct plate count method and membrane filtration method. Standard methods suggested by American water works association were used to analysis the physicochemical parameters of the water samples. RESULTS: The results revealed that the total heterotrophic bacteria, total coliform, and fecal coliform count ranged from 8.9 to 12.6 × 104 cfu/ml, 7.5-11.3 × 102 cfu/ml and 5.7-9.7 × 104 cfu/ml, respectively. The bacterial count results indicated that the river water crossed the WHO-recommended limit of potable water. Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Salmonella, and Shigella species were the common bacterial pathogens isolated from river water samples. The results of the physicochemical analysis revealed that some of the parameters Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD), and turbidity exceeded the maximum permissible limits of WHO and other parameters were below the WHO permissible limits. CONCLUSION: Therefore, the presence of bacterial pathogens, fecal coliform indicators, and some physicochemical parameters of the Kalte River exceeding the recommended limits may expose users of the river water to the risk of infection.